There is a lot of confusing advice about the "optimal" meal frequency.
According to many experts, eating breakfast jump starts fat burning and 5–6 small meals per day prevent your metabolism from slowing down.
But studies actually show mixed results and it is not clear that more frequent meals help you lose weight.
This article explores how many meals you should be eating and discusses the general health relevance of meal frequency.
Metabolic rate is the number of calories your body burns within a given time period.
The idea that eating more frequent, smaller meals increases metabolic rate is a persistent myth.
It is true that digesting a meal raises metabolism slightly and this phenomenon is known as the thermic effect of food. However, it is the total amount of food consumed that determines the amount of energy expended during digestion.
Eating 3 meals of 800 calories will cause the same thermic effect as eating 6 meals of 400 calories. There is literally no difference.
Multiple studies have compared eating many smaller versus fewer larger meals and concluded that there is no significant effect on either metabolic rate or the total amount of fat lost (, ).
Summary Eating more frequently does not increase your overall metabolic rate, or the numbers of calories you burn over the day.
One argument I see a lot is that people should eat often to balance blood sugar levels.
Eating big meals is thought to lead to rapid highs and lows in blood sugar, while eating smaller and more frequent meals should stabilize blood sugar levels throughout the day.
This, however, is not supported by science. Studies show that people who eat fewer, larger meals have lower blood glucose levels, on average (3).
They may have bigger spikes in blood sugar but overall their levels are much lower. This is especially important for people with blood sugar issues since having high blood sugar can cause all sorts of problems.
Less frequent eating has also been shown to improve satiety and reduce hunger compared to more frequent meals ().
When it comes to blood sugar control, breakfast also seems to play a role. Studies show that eating the largest meal of the day in the morning, or early in the day, lowers average daily blood sugar levels ().
Summary Fewer and larger meals lower your average daily blood sugar levels. Getting most of your calories in the morning and eating fewer in the afternoon and evening also seems to reduce average blood sugar levels.
"Breakfast is the most important meal of the day..." or is it?
Conventional wisdom dictates that breakfast is a necessity, that it jump starts your metabolism for the day and helps you lose weight.
What’s more, observational studies consistently show that breakfast skippers are more likely to be obese than people who eat breakfast ().
Yet correlation doesn't equal causation. This data does not prove that breakfast helps you lose weight, just that eating breakfast is associated with a lower risk of being obese.
This is most likely because breakfast skippers tend to be less health-conscious overall, perhaps opting for a doughnut at work and then having a big meal at McDonald's for lunch.
Everyone "knows" that breakfast is good for you, so people who have healthy habits overall are more likely to eat breakfast.
However, there is no evidence that breakfast “jump starts” metabolism and makes you lose weight.
Nevertheless, eating breakfast may benefit certain aspects of health. It appears that the body’s blood sugar control is better in the morning ().
Therefore, having a high-calorie breakfast results in lower average daily blood sugar levels compared to eating a high-calorie dinner ().
Also, one study in people with type 2 diabetes found that fasting until noon increased the rise in blood sugar after lunch and dinner ().
These effects are mediated by the body clock, also known as the circadian rhythm, but more studies are needed before scientists can fully understand how it works.
People with diabetes and those who are concerned about their blood sugar levels should consider eating a healthy breakfast.
But as general advice: If you are not hungry in the morning, skip breakfast. Just make sure to eat healthy for the rest of the day.
Summary There is no evidence that skipping breakfast is harmful to healthy people. However, people with diabetes should consider eating a healthy breakfast or getting most of their calories early in the day.
Intermittent fasting is a trendy topic in nutrition these days.
It means that you strategically abstain from eating at certain times, such as skipping breakfast and lunch each day or doing two longer 24-hour fasts each week.
According to conventional wisdom, this approach would put you in "starvation mode" and make you lose your precious muscle mass.
However, this is not the case.
Studies on short-term fasting show that the metabolic rate may actually increase in the beginning. Only after prolonged fasting does it go down (, ).
Additionally, studies in both humans and animals show that intermittent fasting has various health benefits, including improved insulin sensitivity, lower glucose, lower insulin and various other benefits ().
Intermittent fasting also induces a cellular clean-up process called autophagy, where the body's cells clear waste products that build up in the cells and contribute to aging and disease ().
Summary Skipping meals every now and then helps you lose weight and may improve your blood sugar control over time.
There are no health benefits to eating more often. It doesn't increase the number of calories burned or help you lose weight.
Eating more often also doesn't improve blood sugar control. If anything, eating fewer meals is healthier.
It seems quite clear that the myth of frequent, small meals is just that — a myth.
So I'm going to propose a radical new idea for timing your meals:
- When hungry, eat
- When full, stop
- Repeat indefinitely